Method of applying screws to work



June 16, 1942- M. R. Hu-rcHlsoN, JR 2,286,309

METHOD OF PPLYING SCREWS'TO WORK l original Filed Nov. 28, 1939 MmLER RHUTCHISOMJR INVENTOR BY AM/.;

' ATTORNEYS A Patented June 16, 1942 METHOD F APPLYING SCREWS TO WORK Miller R. Hutchison, Jr., Rochester, N. Y., assignor to Eastman Kodak Company, Rochester,

N. Y., a corporationlof New Jersey Original application November 28, 1939, Serial No. 306,505. Divided and this application April 30,

1940, Serial No. 332,572

4 Claims.

This invention relates to the application of screws to work.

One object of my invention is to provide a method for rapidly applying screws, particularly small screws, to tapped holes. Another object of my invention is to provide a method of driving screws, which eliminates entering the individual screws into the openings adapted to receive them one at a tim-e and which greatly speeds up the operation of driving screws, into work. Still another object of my invention is to provide a method of applying screws into work in which each screw will be seated in the work by a substantially light torque which is selected to prevent stripping the screw threads and to insure seating each screw firmly in place. Another object of my invention is to prevent a rapid means of applying a series of screws to the threaded openings, and other objects -will appear from the following specification,- the novel features being particularly pointed out in the claims at the end thereof.

Coming now to the drawing, wherein like reference characters denote like parts throughout:

Fig- 1 is a sectional view through a typical screw driver constructed in accordance with and embodying a preferred form of my invention.

Fig. 2 is a side elevation of the screw driver shown in Fig. 1.

Figs. 3, 4 and 5 are each cross-sections on lines 3-3, 5 4 and 5-5 of Fig. 1.

Fig. 6 is an enlarged detail section showing the screw driving end of my screw driver.

'Ihis application is a division of my copending application Serial No. 306,505, led November 28, 1939, now Patent No. 2,247,500, dated July 1,

1941, for Screw driver and method of applying screws therewith.

In applying screws, and particularly in applying small screws to tapped openings, there are a great many difficulties which consume considerable time and which, in many instances, require skill. For instance, when extremely small screws are being applied, such as` are used in watches, photographic shutters and the like, considerable skill is required on the part of the operator to tighten the screw to the desired amount, without applying such torque to the screw as may strip the screw threads but suiilcient to assure that the screw will hold properly. This cannot readily be done with small screws. Another difliculty is handling small screws, turning them until the screw slot engages the end of the normal type of screw driver, and positioning them in the work. Magnetic screw drivers afford some assistance, where they can be used, but even such screw drivers make it necessary to pick up and position the screws.

In accordance with my invention, I propose to utilize sticks of screws which may be successively advanced in a screw driver, or byother means. and to apply a torque to a screw other than the screw being driven into the work, so that a narrow, frangible neck connecting the driven screw to the driving screw will break when the screw being driven has been sufficiently tightened in its tapped hole. I propose toemploy sticks of screws connected by narrow, frangible necks, the diameter and strength of which may be so regulated that two screws will break apart when the driven screw has been firmly seated in its aperture. Such screw sticks may be made of any length, and I have found that from 20 to 50 screws in a stick is suitable for most purposes. since such a stick can be inserted into 'a screw driver of convenient length for application to work. It is possible, of course, to use other types of screw drivers for driving in screws by my improved method, but for many purposes the screw driver shown in the present application has been found to be highly desirable, and is quite suitable as an illustration of one way of carrying out my improved method of applying screws.

Referring to Fig. 2, as an embodiment of a suitable type of screw driver, I have shown a. screw driver comprising a hollow handle I, having a Y screw driving end 2 and a screw advancing member 3, which preferably includes the usual type of rotatable knob 4. The screw advancing member 3 can slide in an..upper hollow end 5 of the handle I, its movement being limited by means of a screw 6 and a slot 1, the effective length of which can be altered by means oi a collar 8, threaded at 9 to the handle I. Thus, by moving the collar 8 back and forth, the extent ofmovement of the screw advancing member 3 can be controlled to an extent suitable to care for screws of varying lengths.

The screw advancing member 3 is provided with a shoulder I0, against which one end of a spring II rests, the other end ofthe spring resting against a shoulder I2 in the bore 5 of the handle. Thus, the screw advancing end 3 is normally held in the raised position shown in Fig. 1 so that an advancing spring I3 connected by a screw I3 to the tubular advancing member 3 can lie in the position shown in Fig. 1 with the ange I4 engaging the head H of a screw S,

` stick are used as the handle of the screw driver which is next adjacent a second screw S' which is being driven into the work.

A holding spring I5 is attached to the handle I by means of a screw I6, this holding spring having a shoulder I adapted to rest against the head H of the screw being driven into the work.

Particular attention is called to the factv that in the present instance the heads H of the screws are hexagonal in shape and, as indicated in Fig. 4, the hollow portion I8 of the handle I has a complementary shaped hexagonal opening I9 in which the hexagonal heads H may slide freely, but in which they may not turn. Thus, when the handle I ls turned, the heads H will be turned. It should also be noticed that Fig. 5 provides a rounded opening which does not engage the head H' of the lowermost screw S' to such an extent that it will rotate the head, although the edges of the head H' may, if desired, closely approach the bore 20 to be guided by this bore. Thus. the screw being applied to the work does not directly receive any driving force from the screw driving end 2 of the screw driver, but the screw is driven entirely through the next adjacent screw, the head of which engages the polygonal opening. Therefore, when a screw is turned into its tapped opening, the torque applied to the second screw will turn the driven screw until it is seated firmly and by continuing the turning movement and adding to it, if desired, a slight bending movement, the frangible neck N between the two screws is snapped off. Since the size of this neck has been carefully selected, so that the material will be of suilicient strength to rmly seat the driven screw and so that the neck will snap before the threads can be damaged by too great a torque, it will be seen that the proper seating of the screws does not solely depend upon the force applied to the screw driver.

For a full description of the screw sticks, reference may be had to my copending application Serial No. 306,504, led November 28, 1939, now Patent No. 2,247,499, dated July 1, 1941, entitled Screw stick.

After one screw has been` driven into place, the operator merely presses down upon the knob causing the screw advancing member 3 to lower the spring ange it, shoving down the screw stick until the next screw is caught behind the holding spring i5. The operator then twists the screw driver rapidly until the' screw is firmly seated in its tapped aperture and the neck N is twisted off. Thus, one screw after another may be applied at very high speed to the work without the necessity of picking up the individual screws aligning the screw slots and screw driver, positioning the screws in the apertures, and, moreover, with my improved method of applying screws, it is impossible for a careless operator to apply too much or too little torque to a screw and thus strip the thread, sometimes damaging'the work to such an extent that it can only be repaired at considerable expense.

While I have described the screw driver operating on hexagonal screw heads, itis obvious that various different shaped screw heads can be used, and a number of different preferred forms are shown in my copending application above referred t0.

For certain types of work, it is possible to use a screw stick without a screw driver and still carry out my method of applying screws. In such cases, the hexagonal heads of the screw and the lowermost screw may be rapidly screwed into place, and as soon as it becomes rmly seated by continuing the rotative movement and/or at the same time slightly bending the stick arigularly, the breaking force occurs at the neck N, connecting the screw stick to the screw seated in the work. It is also possible to place such screws by means of a power-driven mechanism, although, generally, it is only preferable to use such a mechanism with relatively large screws.

VMy invention is particularly directed to applying extremely small screws towork, because it is with these that the greatest difficulty of handling occurs.

The shape of the screw driver, and particularly the shape of the screw driving end is, of course, made suitable for the shape of the screw heads of the screw stick being used. It is possible to drive in a smooth round screw head by providing a friction type of clutch inside of the screw driver and the screw driver, of course, may be made complemental in shape to any lrregular size screw head which may be desired. Each type of screw head requires a special screw driver, although screws having threaded bodies of diierent lengths may be taken care of by adjusting the movement of the screw advancing mechanism by turning the knurled ring 8 on the thread 9, altering the possible throw of the screw advancing spring I3.

Referring to Fig. l, it should be noticed that a small guiding sleeve 29, which is the same in cross-section as the opening I9 in the lower end of the screw driver, is provided in the upper end of the tubular member 3. The reason for this is that when a screw stick is loaded into theV screw driver, the guiding sleeve 29 positions the heads of the screw stick properly so that they will immediately register with the opening I9, because the screw stick loaded into the screw driver is preferably at least as long as the distance between the guiding sleeve 29 and the operative end 20 of the screw driver.

From my copending application above referred to, it will be seen that some screw sticks may be provided with each side of the hexagonal heads of the screws lying in a single plane, whereas other screw sticks may have heads of different shapes, including round heads. In such cases, the screw driver must have an inside configuration which will drive the particular type of screw heads which are in use.

lt is not essential that the screw driver be provided with the guiding sleeve 29, but I nd that this facilitates loading the screw driver, par. ticularly where the screw stick is not of greater length than the screw driver. Of course, if a. screw stick is loaded into the screw driver which projects a distance from the knob Il, it may still be readily loaded by registering the lowermost screw by twisting the upper end of the screw stick.

After screws have been driven in with the screw driver as described above, it may be necessary to remove them. 'I'his can be done with a screw driver having an end opening complemental in shape to the screw head which is to be removed, so that it may be used to unserew a seated screw or a screw which may have improperly entered the opening into which it was inserted.

One of the advantages of utilizing a screw stick for placing screws in work is that in some mechanisms containing many small parts, such as Watches or photographic shutters, if individual screws are used, an operator is liable to drop a screw into the mechanism and it frequently oc curs that if the mechanism is only partially assembled, it is extremely dropped screw without taking the mechanism apart.` My improved form of screw driver always holds onto the screw'to be used until it is properly seated so that it is diiiicult, if not impossible, to accidentally drop a screw into mechanism being assembled.

When screws are used in a screw driver as described above, the last screw of each screw stick is ordinarily wasted because it is usual to drive each screw into the work through the driving contact with the next adjacent screw or through driving contact with other screws of the stick. p

What I claim is:

l. A method of applying screws to work which comprises utilizing a stick of-coaxially arranged interconnected screws, driving an end screw into the work by rotating the next adjacent screw and continuing such driving movement until the interconnection between the driven screw and the driving screw is broken.

2. A -method of rapidly applying screws to work which comprises utilizing a stick of vcoaxlally arranged screws with frangible necks therebetween, driving a screw into the work by rotating the next adjacent screw until the driven screw is fully seated in the work and continuing diihcult to remove the the rotative movement until the frangible neck between the screws is twisted off thereby iirmly seating said screw in the work.

3. A method of seating screws in threaded apertures by the application of a limited torque thereto comprising utilizing a stick of screws each having heads and threaded shanks and each connected by necks of known strength, which comprises driving one screw into work through a torque applied to the neck connecting it to the next adjacent screw until the driven' screw is seated in the threaded aperture and continuing the application of a torque to the .next adjacent screw until said neck is ruptured whereby only such torque as said neck can stand may be used to seat the driven screw.

V4. A method of seating screws in threaded apertures by the application of a limited torque thereto comprising utilizing a stick of screws each having heads and threaded shanks and each connected by ,necks of known strengthi which comprises driving one screw into work through a torque applied to the neck connecting it to the next adjacent screw until the driven screw is seated in the threaded aperture and turning and bending the next adjacent screw until the neck between said screw and the driven screw is broken whereby said screw may be seated with only a limited torque applied thereto.I

mim R. HU'rcHrsoN, Jn. 

